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Questions and Answers
What is the primary effect of cocaine on neurotransmitter transporters?
What is the primary effect of cocaine on neurotransmitter transporters?
How do methylxanthines lead to stimulation in the central nervous system?
How do methylxanthines lead to stimulation in the central nervous system?
What is a potential consequence of chronic use of benzodiazepines and barbiturates?
What is a potential consequence of chronic use of benzodiazepines and barbiturates?
Which of the following withdrawal symptoms is associated with caffeine abstinence?
Which of the following withdrawal symptoms is associated with caffeine abstinence?
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What mechanism underlies caffeine withdrawal syndrome?
What mechanism underlies caffeine withdrawal syndrome?
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What is the primary difference between acquired and innate tolerance?
What is the primary difference between acquired and innate tolerance?
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Which process is responsible for pharmacokinetic tolerance?
Which process is responsible for pharmacokinetic tolerance?
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How does pharmacodynamic tolerance affect the nervous system?
How does pharmacodynamic tolerance affect the nervous system?
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What effect does alcohol have on GABAA receptors?
What effect does alcohol have on GABAA receptors?
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Which statement best describes the role of NMDA receptors after alcohol consumption?
Which statement best describes the role of NMDA receptors after alcohol consumption?
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What is a potential outcome of long-term drug administration in relation to pharmacodynamic tolerance?
What is a potential outcome of long-term drug administration in relation to pharmacodynamic tolerance?
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What characterizes learned tolerance in the context of drug use?
What characterizes learned tolerance in the context of drug use?
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What role does varenicline play in the treatment of nicotine withdrawal?
What role does varenicline play in the treatment of nicotine withdrawal?
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What is a common withdrawal symptom associated with nicotine cessation?
What is a common withdrawal symptom associated with nicotine cessation?
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Which neurotransmitter's reuptake is inhibited by the antidepressant bupropion?
Which neurotransmitter's reuptake is inhibited by the antidepressant bupropion?
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What mechanism contributes to the reinforcing properties of cocaine?
What mechanism contributes to the reinforcing properties of cocaine?
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What is the primary reason that amphetamines have been largely replaced by safer alternatives in clinical use?
What is the primary reason that amphetamines have been largely replaced by safer alternatives in clinical use?
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What is the effect of nicotine on nAChR activity during withdrawal?
What is the effect of nicotine on nAChR activity during withdrawal?
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What is a clinical use of cocaine related to its mechanism of action?
What is a clinical use of cocaine related to its mechanism of action?
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Which of the following is NOT a variable affecting the development of substance use disorder?
Which of the following is NOT a variable affecting the development of substance use disorder?
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In cigarette smoking, which neurotransmitter is primarily linked with the feelings of well-being associated with nicotine use?
In cigarette smoking, which neurotransmitter is primarily linked with the feelings of well-being associated with nicotine use?
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What is the effect of severing the brain reward pathway or blocking dopamine receptors in the NAc?
What is the effect of severing the brain reward pathway or blocking dopamine receptors in the NAc?
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Which side effect might occur due to augmented dopamine neurotransmission from stimulant use?
Which side effect might occur due to augmented dopamine neurotransmission from stimulant use?
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What effect does the binding of varenicline to nAChRs have on nicotine's activity?
What effect does the binding of varenicline to nAChRs have on nicotine's activity?
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Which statement regarding the pharmacokinetic properties of drugs is accurate?
Which statement regarding the pharmacokinetic properties of drugs is accurate?
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Which of the following correctly describes drug misuse?
Which of the following correctly describes drug misuse?
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What is a characteristic of addictive drugs in relation to the brain's reward pathways?
What is a characteristic of addictive drugs in relation to the brain's reward pathways?
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Which of the following drugs is typically abused despite having accepted medical purposes?
Which of the following drugs is typically abused despite having accepted medical purposes?
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How does drug activation of reward mechanisms correlate with addiction potential?
How does drug activation of reward mechanisms correlate with addiction potential?
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What is the relationship between drug absorption methods and their reinforcing effects?
What is the relationship between drug absorption methods and their reinforcing effects?
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What type of drugs are characterized as having the potential for both misuse and abuse?
What type of drugs are characterized as having the potential for both misuse and abuse?
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What is the primary mechanism through which cocaine affects the central nervous system?
What is the primary mechanism through which cocaine affects the central nervous system?
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Which of the following substances primarily acts as a psychostimulant by increasing monoamine neurotransmitter release?
Which of the following substances primarily acts as a psychostimulant by increasing monoamine neurotransmitter release?
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Which property best describes hallucinogens or psychedelics?
Which property best describes hallucinogens or psychedelics?
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What is the effect of nicotine activation on central nicotinic receptors?
What is the effect of nicotine activation on central nicotinic receptors?
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Which of the following is NOT considered a psychomotor stimulant?
Which of the following is NOT considered a psychomotor stimulant?
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Which of the following inhalants can induce mind-altering effects?
Which of the following inhalants can induce mind-altering effects?
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What type of signaling effect does a psychostimulant typically have on the brain?
What type of signaling effect does a psychostimulant typically have on the brain?
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What characterizes the addiction potential of nicotine?
What characterizes the addiction potential of nicotine?
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Which of the following statements about THC (Tetrahydrocannabinol) is true?
Which of the following statements about THC (Tetrahydrocannabinol) is true?
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What is the primary effect of a psychomotor stimulant such as amphetamine?
What is the primary effect of a psychomotor stimulant such as amphetamine?
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Study Notes
Drug Abuse
- Drug abuse is the use of a substance for a purpose that is not consistent with legal or medical guidelines.
- Drug abuse is used for euphoric feelings.
- Drug misuse is the use of a substance for a purpose that is not consistent with legal medical guidelines, mostly prescription drugs.
- Misuse is mostly related to taking the drug for a faster or better effect, as opposed to using it for its intended purpose
- Psychoactive drugs can be CNS depressants, CNS stimulants, and/or hallucinogens.
Tolerance
- Tolerance is the decreased effect of a drug that develops with continued use.
- Acquired tolerance results from repeated drug administration that shifts the dose-response curve to the right. A larger dose is needed to achieve the same effect as before.
- Innate tolerance refers to pre-existing interindividual variations in sensitivity to a drug. Individual variations in sensitivity occur before the first administration of a drug.
- Acquired tolerance includes pharmacokinetic, pharmacodynamic, and learned components.
- Pharmacokinetic tolerance develops when the body's capacity to metabolize or excrete the drug increases.
- Pharmacodynamic tolerance is caused by neuronal adaptations.
- Short-term drug exposure can alter neurotransmitter release, receptor numbers, ion channel conductance, or signal transduction.
- Longer-term use causes changes in gene expression, related to adaptations of learning and memory.
Alcohol
- Alcohol modulates the central nervous system's major inhibitory and excitatory neurotransmitter systems.
- Alcohol increases chloride conductance through GABA receptors, resulting in cellular hyperpolarization.
- Alcohol decreases calcium conductance through NMDA receptors.
Molecular Adaptations to Chronic Alcohol Exposure
- Internalization and decreased surface expression of "normal" a1 subunit-containing GABA receptors, increased expression of "low alcohol sensitivity" a4 subunit-containing GABA receptors, and increased phosphorylation of NMDA receptors containing "high conductance" NR2B subunits, are all molecular adaptations to chronic alcohol exposure.
- Thus, neuroadaptation results in tolerance to the acute depressant effects of alcohol and occurs concomitantly with dependence.
- During withdrawal, these adaptations result in generalized hyperexcitability of neurons. This results in anxiety, insomnia, delirium, and potentially seizures.
Cocaine
- Acute cocaine exposure inhibits dopamine reuptake transporters (DAT), which leads to an increase in synaptic dopamine. This activation leads to increased activity, and euphoria.
- Increased extrasynaptic dopamine also activates D2 autoreceptors which, in turn, leads to decreased dopamine synthesis.
- During withdrawal, the decreased synaptic dopamine levels and increased clearance through DAT cause activation of postsynaptic dopamine receptors. Feelings of dysphoria, fatigue, and anhedonia result.
Dependence
- The dependence can be physical and psychological.
- Physical dependence is characterized by withdrawal symptoms upon discontinuation of the drug.
- New terminology for physical dependence is dependence.
- Psychological dependence is characterized by craving for the drug, even after acute withdrawal symptoms subside.
- The individual is prone to relapse.
- New terminology for psychological dependence is addiction.
Addiction
- Addiction refers to substance dependence.
- Drug-seeking behavior is fundamental to this.
- Addiction is described as "rewiring" of the brain due to persistent adaptations to drug use.
- Cravings and relapses can occur long after cessation.
Dependence
- The medial forebrain bundle and ventral tegmental area (VTA) are termed "pleasure centers" or reward areas.
- A subset of dopaminergic neurons from the VTA project to the nucleus accumbens (NAc).
- These neurons are crucial for the brain reward pathway and behavior reinforcement.
Variables Affecting the Development of Substance Use Disorders
- The development of substance use disorders depends on: the nature of the drug, genetic factors, acquired psychological factors, social traits of the drug user, and environmental factors.
- The ability of a drug to activate reward mechanisms is strongly correlated to its ability to cause addiction.
- Pharmacokinetic properties of the drug influence its effects on the brain. The faster the drug is absorbed into the body and reaches target neurons, the greater the activation of reward pathways.
- Rapid elimination is more likely to lead to addiction than drugs with slower elimination.
- This is due to the maintenance of drug concentration at target sites for a longer duration, thus diminishing the severity of withdrawal symptoms.
Drug misuse and abuse
- Drug misuse is the use of a substance for a purpose not consistent with its legal or medical guidelines.
- examples: taking over-the-counter medications for unapproved purposes of duration and dose for faster medical effect or to feel better.
- Drug abuse: using a substance to elicit or enhance feelings, like certain sensations or to increase excitement.
Drugs of Abuse
- All of the substances listed are described as drugs of abuse because they are used in ways that have not been medically approved
- Addictive drugs usually activate the mesolimbic dopamine reward pathway.
Agents that Can Cause Dependence
- These can be CNS depressants or CNS stimulants.
Psychostimulants
- Psychostimulants are psychotropic substances stimulating the central nervous system.
- They cause excitation, elevated mood, increased alertness, and arousal.
- Examples include amphetamines, cocaine, caffeine, nicotine
Methylxanthines
- Methylxanthines, including caffeine, theophylline, and theobromine, are CNS stimulants.
- Found in coffee, tea, soda, chocolate etc.
- They have alerting effects, improve performance, and can cause insomnia.
- Adenosine is blocked by these substances, leading to dopamine and norepinephrine release in the brain.
CNS Depressants
- This class includes barbiturates, benzodiazepines, ethanol, methanol, inhalants, and opioids.
- Sedative and hypnotic properties are often described for these substances.
- They also have anxiolytic effects to reduce tension.
- Use for these purposes can be inappropriate.
Benzodiazepines and Barbiturates
- These are sedative/hypnotic agents widely used for anxiety and insomnia.
- Euphoria can be associated with use during intoxication.
- Anxiolytic and tension-reducing properties may enhance the reinforcing effects and abuse potential of these drugs.
- They increase the efficiency of GABAergic pathways, but chronic use can induce down-regulation of these pathways via neuroadaptation.
Alcohol
- Depression of inhibitory control leads to euphoria and CNS stimulation as early effects of alcohol.
- Higher blood alcohol levels result in impaired motor coordination, emotional control, and judgment.
- Overdose can lead to respiratory depression, and withdrawal can be life-threatening.
- Ethanol affects GABA receptors, NMDA glutamate receptors, and cannabinoid receptors.
Opiates
- Opiates are CNS depressants derived from the poppy plant.
- Common opiates include opium, heroin, morphine, and codeine.
Opioids
- Addicts describe an intense euphoric feeling (rush) associated with the intravenous injection of heroin.
- Sites of action of these opioids in the brain reward system are in the ventral tegmental area, where GABAergic interneurons tonically inhibit the dopaminergic neurons involved in the reward pathway in the nucleus accumbens.
- Administration of exogenous opioids decreases GABA release and increases dopamine release, resulting in a strong reward response in the nucleus accumbens.
Treatment of Addiction
- Pharmacological treatment: Detoxification is the first step.
- The goal is to allow the body to adapt to the absence of the drug/alcohol, and prepare the patient for long-term rehabilitation.
- Chronic treatment strategies involve administration of an agent generating aversive effects.
- Example: disulfiram inhibits aldehyde dehydrogenase, leading to acetaldehyde accumulation and aversive symptoms like facial flushing, headache, nausea.
- Another strategy is opioid antagonists like naltrexone, to block the effects of the drug on opioid receptors, thus preventing the high.
- Psychosocial treatment: includes cognitive behavioral therapy and self-help programs like Alcoholics Anonymous. Integration of pharmacological and psychosocial approaches often results in a better outcome.
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Description
Explore the concepts of drug abuse and tolerance in this quiz. Learn about the differences between misuse and abuse, the effects of psychoactive drugs, and how tolerance develops over time. This quiz will help you understand the complexities of drug use and its implications.
